Assertion failure in serialization when building swift-syntax with swift-6.2-DEVELOPMENT-SNAPSHOT-2025-09-20-a_wasm #84431
Description
Description
#84140 hasn't been resolved in the release/6.2 branch yet.
Reproduction
Same as #84140.
https://github.com/kkebo/swift-syntax/actions/runs/17892760070/job/50875355850#step:10:470
Stack dump
swift-frontend: /home/build-user/llvm-project/llvm/include/llvm/Bitcode/BitcodeConvenience.h:94: static void llvm::BCFixed<1>::assertValid(const T &) [Width = 1, T = unsigned int]: Assertion `llvm::isUInt<Width>(data) && "data value does not fit in the given bit width"' failed.
Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the crash backtrace.
Stack dump:
0. Program arguments: /usr/bin/swift-frontend -frontend -emit-module -experimental-skip-non-inlinable-function-bodies-without-types /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/CompilerPluginMessageHandler.swift /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/Diagnostics.swift /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/JSON/CodingUtilities.swift /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/JSON/JSON.swift /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/JSON/JSONDecoding.swift /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/JSON/JSONEncoding.swift /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/LRUCache.swift /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/Macros.swift /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/PluginMacroExpansionContext.swift /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/PluginMessageCompatibility.swift /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/PluginMessages.swift /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/StandardIOMessageConnection.swift -target wasm32-unknown-wasip1 -disable-objc-interop -sdk /root/.swiftpm/swift-sdks/swift-6.2-DEVELOPMENT-SNAPSHOT-2025-09-20-a_wasm.artifactbundle/swift-6.2-DEVELOPMENT-SNAPSHOT-2025-09-20-a_wasm/wasm32-unknown-wasip1/WASI.sdk -I /__w/swift-syntax/swift-syntax/.build/wasm32-unknown-wasip1/debug/Modules -no-color-diagnostics -Xcc -fno-color-diagnostics -enable-testing -g -debug-info-format=dwarf -dwarf-version=4 -module-cache-path /__w/swift-syntax/swift-syntax/.build/wasm32-unknown-wasip1/debug/ModuleCache -swift-version 6 -Onone -D SWIFT_PACKAGE -D DEBUG -D SWIFT_MODULE_RESOURCE_BUNDLE_UNAVAILABLE -empty-abi-descriptor -resource-dir /root/.swiftpm/swift-sdks/swift-6.2-DEVELOPMENT-SNAPSHOT-2025-09-20-a_wasm.artifactbundle/swift-6.2-DEVELOPMENT-SNAPSHOT-2025-09-20-a_wasm/wasm32-unknown-wasip1/swift.xctoolchain/usr/lib/swift_static -use-static-resource-dir -enable-anonymous-context-mangled-names -file-compilation-dir /__w/swift-syntax/swift-syntax -Xcc -fmodule-map-file=/__w/swift-syntax/swift-syntax/Sources/_SwiftSyntaxCShims/include/module.modulemap -Xcc -I -Xcc /__w/swift-syntax/swift-syntax/Sources/_SwiftSyntaxCShims/include -Xcc --sysroot -Xcc /root/.swiftpm/swift-sdks/swift-6.2-DEVELOPMENT-SNAPSHOT-2025-09-20-a_wasm.artifactbundle/swift-6.2-DEVELOPMENT-SNAPSHOT-2025-09-20-a_wasm/wasm32-unknown-wasip1/WASI.sdk -Xcc -g -no-auto-bridging-header-chaining -module-name SwiftCompilerPluginMessageHandling -package-name swift_syntax -in-process-plugin-server-path /usr/lib/swift/host/libSwiftInProcPluginServer.so -plugin-path /usr/lib/swift/host/plugins -plugin-path /usr/local/lib/swift/host/plugins -emit-module-doc-path /__w/swift-syntax/swift-syntax/.build/wasm32-unknown-wasip1/debug/Modules/SwiftCompilerPluginMessageHandling.swiftdoc -emit-module-source-info-path /__w/swift-syntax/swift-syntax/.build/wasm32-unknown-wasip1/debug/Modules/SwiftCompilerPluginMessageHandling.swiftsourceinfo -emit-objc-header-path /__w/swift-syntax/swift-syntax/.build/wasm32-unknown-wasip1/debug/SwiftCompilerPluginMessageHandling.build/include/SwiftCompilerPluginMessageHandling-Swift.h -serialize-diagnostics-path /__w/swift-syntax/swift-syntax/.build/wasm32-unknown-wasip1/debug/SwiftCompilerPluginMessageHandling.build/SwiftCompilerPluginMessageHandling.emit-module.dia -emit-dependencies-path /__w/swift-syntax/swift-syntax/.build/wasm32-unknown-wasip1/debug/SwiftCompilerPluginMessageHandling.build/SwiftCompilerPluginMessageHandling.emit-module.d -parse-as-library -o /__w/swift-syntax/swift-syntax/.build/wasm32-unknown-wasip1/debug/Modules/SwiftCompilerPluginMessageHandling.swiftmodule
1. Swift version 6.2-dev (LLVM bbea9d7fa920a45, Swift 9016636714dfba0)
2. Compiling with the current language version
3. While evaluating request ExecuteSILPipelineRequest(Run pipelines { Non-Diagnostic Mandatory Optimizations, Serialization } on SIL for SwiftCompilerPluginMessageHandling)
4. While running pass #2155 SILModuleTransform "SerializeSILPass".
5. While serializing 'wasmPump()' (at /__w/swift-syntax/swift-syntax/Sources/SwiftCompilerPluginMessageHandling/CompilerPluginMessageHandler.swift:287:1)
#0 0x000055f96a3efae8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/usr/bin/swift-frontend+0x8bf6ae8)
#1 0x000055f96a3ed60e llvm::sys::RunSignalHandlers() (/usr/bin/swift-frontend+0x8bf460e)
#2 0x000055f96a3f0181 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
#3 0x00007f2017cb2520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
#4 0x00007f2017d069fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
#5 0x00007f2017cb2476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
#6 0x00007f2017c987f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
#7 0x00007f2017c9871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
#8 0x00007f2017ca9e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
#9 0x000055f963873740 void llvm::detail::BCRecordCoding<llvm::BCLiteral<327ul>, llvm::BCFixed<1u>, llvm::BCFixed<1u>, llvm::BCVBR<4u>, llvm::BCVBR<4u>, llvm::BCBlob>::emit<llvm::SmallVector<unsigned long, 64u>, unsigned int, bool, unsigned int, unsigned long, unsigned long, llvm::SmallString<32u>&>(llvm::BitstreamWriter&, llvm::SmallVector<unsigned long, 64u>&, unsigned int, unsigned int, bool&&, unsigned int&&, unsigned long&&, unsigned long&&, llvm::SmallString<32u>&) crtstuff.c:0:0
#10 0x000055f9638639e4 swift::serialization::Serializer::DeclSerializer::writeDeclAttribute(swift::Decl const*, swift::DeclAttribute const*) crtstuff.c:0:0
#11 0x000055f96385305e swift::serialization::Serializer::DeclSerializer::visit(swift::Decl const*) crtstuff.c:0:0
#12 0x000055f963852c77 swift::serialization::Serializer::writeASTBlockEntity(swift::Decl const*) (/usr/bin/swift-frontend+0x2059c77)
#13 0x000055f963854ee8 bool swift::serialization::Serializer::writeASTBlockEntitiesIfNeeded<swift::serialization::Serializer::ASTBlockRecordKeeper<swift::Decl const*, llvm::PointerEmbeddedInt<unsigned int, 31>, 2u>>(swift::serialization::Serializer::ASTBlockRecordKeeper<swift::Decl const*, llvm::PointerEmbeddedInt<unsigned int, 31>, 2u>&) (/usr/bin/swift-frontend+0x205bee8)
#14 0x000055f963854d0d swift::serialization::Serializer::writeAllDeclsAndTypes() (/usr/bin/swift-frontend+0x205bd0d)
#15 0x000055f963856da2 swift::serialization::Serializer::writeAST(llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>) (/usr/bin/swift-frontend+0x205dda2)
#16 0x000055f9638602ce swift::serialization::Serializer::writeToStream(llvm::raw_ostream&, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::SILModule const*, swift::SerializationOptions const&, swift::fine_grained_dependencies::SourceFileDepGraph const*) (/usr/bin/swift-frontend+0x20672ce)
#17 0x000055f962aeb17a bool llvm::function_ref<bool (llvm::raw_pwrite_stream&)>::callback_fn<swift::serialize(llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::SerializationOptions const&, swift::symbolgraphgen::SymbolGraphOptions const&, swift::SILModule const*, swift::fine_grained_dependencies::SourceFileDepGraph const*)::$_3>(long, llvm::raw_pwrite_stream&) Serialization.cpp:0:0
#18 0x000055f9624edaab swift::withOutputPath(swift::DiagnosticEngine&, llvm::vfs::OutputBackend&, llvm::StringRef, llvm::function_ref<bool (llvm::raw_pwrite_stream&)>) crtstuff.c:0:0
#19 0x000055f962aeaef3 swift::serialize(llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::SerializationOptions const&, swift::symbolgraphgen::SymbolGraphOptions const&, swift::SILModule const*, swift::fine_grained_dependencies::SourceFileDepGraph const*) (/usr/bin/swift-frontend+0x12f1ef3)
#20 0x000055f962748086 bool llvm::function_ref<bool (swift::fine_grained_dependencies::SourceFileDepGraph&&)>::callback_fn<performCompileStepsPostSILGen(swift::CompilerInstance&, std::unique_ptr<swift::SILModule, std::default_delete<swift::SILModule>>, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, int&, swift::FrontendObserver*)::$_3::operator()() const::'lambda'(swift::fine_grained_dependencies::SourceFileDepGraph&&)>(long, swift::fine_grained_dependencies::SourceFileDepGraph&&) FrontendTool.cpp:0:0
#21 0x000055f9645caded swift::fine_grained_dependencies::withReferenceDependencies(llvm::PointerUnion<swift::ModuleDecl const*, swift::SourceFile const*>, swift::DependencyTracker const&, llvm::vfs::OutputBackend&, llvm::StringRef, bool, llvm::function_ref<bool (swift::fine_grained_dependencies::SourceFileDepGraph&&)>) (/usr/bin/swift-frontend+0x2dd1ded)
#22 0x000055f962747f68 std::_Function_handler<void (), performCompileStepsPostSILGen(swift::CompilerInstance&, std::unique_ptr<swift::SILModule, std::default_delete<swift::SILModule>>, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, int&, swift::FrontendObserver*)::$_3>::_M_invoke(std::_Any_data const&) FrontendTool.cpp:0:0
#23 0x000055f963a4d544 swift::SILModule::serialize() (/usr/bin/swift-frontend+0x2254544)
#24 0x000055f9632b5f30 SerializeSILPass::run() crtstuff.c:0:0
#25 0x000055f9631360a7 swift::SILPassManager::runModulePass(unsigned int) (/usr/bin/swift-frontend+0x193d0a7)
#26 0x000055f963138a2b swift::SILPassManager::execute() (/usr/bin/swift-frontend+0x193fa2b)
#27 0x000055f963132178 swift::SILPassManager::executePassPipelinePlan(swift::SILPassPipelinePlan const&) (/usr/bin/swift-frontend+0x1939178)
#28 0x000055f96313212d swift::ExecuteSILPipelineRequest::evaluate(swift::Evaluator&, swift::SILPipelineExecutionDescriptor) const (/usr/bin/swift-frontend+0x193912d)
#29 0x000055f963154e8a swift::SimpleRequest<swift::ExecuteSILPipelineRequest, std::tuple<> (swift::SILPipelineExecutionDescriptor), (swift::RequestFlags)1>::evaluateRequest(swift::ExecuteSILPipelineRequest const&, swift::Evaluator&) crtstuff.c:0:0
#30 0x000055f963140426 swift::ExecuteSILPipelineRequest::OutputType swift::Evaluator::getResultUncached<swift::ExecuteSILPipelineRequest, swift::ExecuteSILPipelineRequest::OutputType swift::evaluateOrFatal<swift::ExecuteSILPipelineRequest>(swift::Evaluator&, swift::ExecuteSILPipelineRequest)::'lambda'()>(swift::ExecuteSILPipelineRequest const&, swift::ExecuteSILPipelineRequest::OutputType swift::evaluateOrFatal<swift::ExecuteSILPipelineRequest>(swift::Evaluator&, swift::ExecuteSILPipelineRequest)::'lambda'()) crtstuff.c:0:0
#31 0x000055f96313236f swift::executePassPipelinePlan(swift::SILModule*, swift::SILPassPipelinePlan const&, bool, swift::irgen::IRGenModule*) (/usr/bin/swift-frontend+0x193936f)
#32 0x000055f96314205d swift::runSILPassesForOnone(swift::SILModule&) (/usr/bin/swift-frontend+0x194905d)
#33 0x000055f962ab0594 swift::CompilerInstance::performSILProcessing(swift::SILModule*) (/usr/bin/swift-frontend+0x12b7594)
#34 0x000055f962742d47 performCompileStepsPostSILGen(swift::CompilerInstance&, std::unique_ptr<swift::SILModule, std::default_delete<swift::SILModule>>, llvm::PointerUnion<swift::ModuleDecl*, swift::SourceFile*>, swift::PrimarySpecificPaths const&, int&, swift::FrontendObserver*) FrontendTool.cpp:0:0
#35 0x000055f962741e93 swift::performCompileStepsPostSema(swift::CompilerInstance&, int&, swift::FrontendObserver*) (/usr/bin/swift-frontend+0xf48e93)
#36 0x000055f96275386a withSemanticAnalysis(swift::CompilerInstance&, swift::FrontendObserver*, llvm::function_ref<bool (swift::CompilerInstance&)>, bool) FrontendTool.cpp:0:0
#37 0x000055f962744bfe performCompile(swift::CompilerInstance&, int&, swift::FrontendObserver*) FrontendTool.cpp:0:0
#38 0x000055f962743ca8 swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) (/usr/bin/swift-frontend+0xf4aca8)
#39 0x000055f9624c0dcb swift::mainEntry(int, char const**) (/usr/bin/swift-frontend+0xcc7dcb)
#40 0x00007f2017c99d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#41 0x00007f2017c99e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#42 0x000055f9624bfdc5 _start (/usr/bin/swift-frontend+0xcc6dc5)
Expected behavior
It won't crash.
Environment
Swift version 6.2-dev (LLVM bbea9d7fa920a45, Swift 9016636714dfba0)
Additional information
I believe that there are a few possible solutions.
- Option 1: Cherry-pick [wasm] Fix
@_expose(wasm)serialization crash #84215 into the release/6.2 branch - Option 2: Revert [cxx-interop] Add attribute to hide Swift declarations from interop #84053